The present invention relates to a control for determining a firing timing of an internal-combustion engine (which will be hereinafter referred to as an “engine”).
Conventionally, a technique for determining a firing timing or a firing delay in an engine has been proposed. For example, Japanese Patent Application Publication No. 2006-242146 proposes a technique for determining a firing timing or a firing delay based on a difference between a pressure (in-cylinder pressure) in a combustion chamber of an engine which is measured during a compression stroke and an estimated value for a pressure in the combustion chamber in a case where a misfire occurs (such a pressure is referred to as a “motoring pressure”).
Based on the determined firing timing, operating parameters for the engine may be calculated and/or various controls such as a fuel control, an ignition timing control or the like in the engine may be performed. In order to improve the accuracy of such controls, it is desirable to improve the accuracy in determining the firing timing.